(1) Field of the Invention
The present invention relates to the precise exercise of control over the gravity flow of liquid from a reservoir to a consuming unit and particularly to regulating fluid flow in the form of discrete drops in the intravenous application of the fluid to a patient. More particularly, the present invention is directed to a microcomputer based dual intravenous fluid flow control system and to a drop sensor unit employed in such system. Accordingly, the general objects of the present invention are to provide novel and improved devices of the foregoing character.
(2) Description of the Prior Art
The present invention has particular application to medical applications wherein the flow rate and/or total quantity of a liquid being gravity fed intravenously to a patient must be precisely controlled. U.S. Pat. No. 4,372,304 discloses a flow control system which employs a microprocessor based flow control. The flow control system employs a keyboard through which information may be inputted and includes a visual display of parameters which are of interest to the operator. The microprocessor provides output signals to a stepper motor which is coupled to a restrictor having a plunger. The microprocessor provides control signals to a stepper motor which through appropriate gearing causes movement of the plunger so as to increase or decrease the compression of the plastic tube of an IV set which is captured in a disposable adaptor mounted in registration with the plunger.
U.S. Pat. No. 4,094,318 discloses an electronic control apparatus for controlling the administration of a plurality of separate fluids independently and consecutively. The electronic control apparatus includes electrical circuitry which is connected with a plurality of valve operators to operate magnetically operated valves in a plurality of sets to control flow therethrough.